This invention is directed to a method of making oil-in-water (O/W) emulsions and microemulsions and water-in-oil (W/O) emulsions and microemulsions containing silanes or siloxanes having quaternary ammonium groups as an oil phase. In particular, the silanes or siloxanes are obtained by reacting organic quaternary ammonium compounds having epoxide or halohydrin groups, with silanes or siloxanes having amino groups; and the reaction is carried out in the presence of a surfactant in an aqueous polar phase.
Copending application U.S. Ser. No. 10/001,760, filed Oct. 24, 2001, entitled Silicon Based Quaternary Ammonium Functional Compositions and Methods for Making Them (the 760 application); and copending application U.S. Ser. No. 10/001,753, filed Oct. 24, 2001, entitled Silicon Based Quaternary Ammonium Functional Compositions and Their Applications (the ""753 application), are both assigned to the same assignee as the present application, and incorporated herein by reference.
As noted in the ""753 and ""760 applications, quaternary ammonium functional silanes and quaternary ammonium functional siloxanes have a variety of commercial application in the textile industry and in the personal care arena They can also be used as anti-microbial agents; in modifying fillers, fibers, and surfaces; as thickening agents; and as a conditioning agent.
In many of these applications and uses, it is often necessary to deliver the quaternary ammonium functional silanes and the quaternary ammonium functional siloxanes as an emulsion or microemulsion. When an emulsion is required, conventional wisdom dictates that the quaternary ammonium functional silane or quaternary ammonium functional siloxane be combined with a surface active agent and water, and mixed until the emulsion is formed.
It is often inconvenient for end users of quaternary ammonium functional silanes and siloxanes to prepare emulsions and microemulsions, and so it would be beneficial to provide a new and simpler process for preparing the emulsions.
While the ""753 application describes a method of making emulsions containing quaternary ammonium functional silanes and quaternary ammonium functional siloxanes, the process involves application of conventional wisdom, i.e., the quaternary ammonium functional silane or siloxane is combined with a surface active agent and water, and mixed until an emulsion is formed.
The process according to the present application however, differs significantly from the process used in the ""753 application, in that quaternary ammonium functional silanes or siloxanes are actually synthesized in an emulsion, using monomers as starting materials which are reacted together to form the quaternary ammonium functional silane or siloxane, rather than using quaternary ammonium functional silanes or siloxanes.
This invention relates to methods of making certain oil-in-water (O/W) or water-in-oil (W/O) emulsions and microemulsions containing organosilicon compositions as the oil phase. In particular, these emulsions and microemulsions contain silanes or siloxanes having quaternary ammonium groups in their molecule as the oil phase, the silanes or siloxanes having quaternary ammonium groups having been obtained by reacting (i) an organic quaternary ammonium compound having epoxide groups or halohydrin groups in its molecule, with (ii) a silane or siloxane having amino groups in its molecule, in the presence of (iii) a surfactant, components (i)-(iii) being dispersed in (iv) an aqueous polar phase.
Representative of suitable quaternary ammonium compounds having epoxide groups and halohydrin groups are glycidyl trimethylammonium chloride, and (3-chloro-2-hydroxypropyl)trimethylammonium chloride, respectively. The aqueous polar phase may consist of water, it may comprise a mixture of water and a volatile low molecular weight polysiloxane, or it may be a mixture of water and a polar organic compound such as 1,2-hexanediol. These emulsions and microemulsions are useful as treating agents for the hair, skin, and the underarm areas of the human body.
These and other features of the invention will become apparent from a consideration of the detailed description.
As noted above, the invention is directed to oil-in-water (O/W) and water-in-oil (W/O) emulsions and microemulsions containing silanes or siloxanes having quaternary ammonium groups in their molecule as the oil phase. The silanes or siloxanes having quaternary ammonium groups are obtained by reacting (i) an organic quaternary ammonium compound having epoxide groups or halohydrin groups in its molecule, with (ii) a silane or siloxane having amino groups in its molecule. The reaction of components (i) and (ii) is carried out in the presence of (iii) a surfactant, with components (i)-(iii) being dispersed in (iv) an aqueous polar phase.
These materials are essentially the reaction product obtained by combining components (i) and (ii). A detailed showing of their composition in terms of its structure can be found in detail in the ""753 and ""760 applications.
Generally, these materials can be described, for purposes herein, as being silanes or siloxanes having in their molecule at least one unit containing a group such as xe2x80x94Rxe2x80x94Zxe2x80x94Q bonded to silicon in which:
R is a divalent hydrocarbon group such as ethylene,
Z is a group such as xe2x80x94N(Q1)xe2x80x94; and
Q is a group such as xe2x80x94CH(R)CH(OH)YN+(R1)(R2)(R3)Xxe2x88x92;
wherein:
Q1 is a monovalent hydrocarbon group such as methyl;
Y is a divalent hydrocarbon group such as ethylene;
X is a counter ion such as chloride Clxe2x88x92;
and R1-R3 are monovalent hydrocarbon groups such as methyl.
A representative example therefore of at least one particularly preferred xe2x80x94Rxe2x80x94Zxe2x80x94Q group is CH2CH(OH)CH2N+(CH3)2(CH3)Clxe2x88x92.
Reference may be had to the ""753 and ""760 applications for a detailed showing of the generic formulas of compounds of this type. Suffice to say, for the purposes herein, some specific examples of useful compounds of this type are glycidyl trimethylammonium chloride and glycidyl trimethylammonium bromide. While non-terminal epoxides may also be used, terminal epoxides such as the compounds described are generally preferred. Combinations of epoxides may also be employed, as well as combinations of epoxides and the halohydrins noted below.
Again, reference may be had to the ""753 and ""760 applications for a detailed showing of the generic formulas of compounds of this type. Suffice to say, for the purposes herein, some specific examples of useful compounds of this type are
(3-chloro-2-hydroxypropyl)trimethylammonium chloride ClCH2CH(OH)CH2N(CH3)3Cl,
(3-chloro-2-hydroxypropyl)dimethyldodecylammonium chloride,
(3-chloro-2-hydroxypropyl)dimethyloctadecylammonium chloride,
(3-chloro-2-hydroxypropyl)trimethylammonium bromide,
(3-chloro-2-hydroxypropyl)dimethyldodecylammonium bromide, and
(3-chloro-2-hydroxypropyl)dimethyloctadecylammonium bromide.
While non-terminal halohydrins may also be used, terminal halohydrins such as the compounds described are generally preferred. Combinations of halohydrins may also be employed, as well as combinations of halonydrins and the epoxides noted above.
Silanes containing amino groups for use herein generally comprise organosilicon monomers of the type R3SiR wherein the R groups in the molecule can consist of alkyl groups containing 1-6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, and isobutyl; an aryl group such as phenyl; or the R groups can comprise amino groups such as aminoethyl, aminopropyl, aminoisobutyl, aminoethylaminopropyl, and aminoethylaminoisobutyl; provided at least one R group in the silane is an amino group.
Some representative examples of silanes containing amino groups which are suitable for use herein include aminomethyltrimethylsilane, aminotrimethylsilane, (benzylmethylamino)triethylsilane, diethylaminomethyltrimethylsilane, diethylaminotrimethylsilane, diethylaminotriphenylsilane, diisopropylaminotrimethylsilane, dimethylaminotriethylsilane, dimethylaminotrimethylsilane, phenylmethylbis(dimethylamino)silane, tetrakis(dimethylamino)silane, tri-n-hexylsilylamine, trimethylaminosilane, triphenylaminosilane, tris(dimethylamino)ethylsilane, tris(dimcthylamino)methylsilane, and tris(dimethylamino)phenylsilane.
Some examples of siloxanes with amino groups include those siloxane polymers and copolymers having number average molecular weights of 1,000-100,000, especially those having number average molecular weight of 5,000-50,000, such as aminopropyl terminated polydimethylsiloxanes and trimethylsilyl terminated dimethylsiloxane copolymers. The siloxanes should also contain 0.1-2.0 milliequivalents of amino functionality per gram of the siloxane on average, based on amino nitrogen of primary and secondary amino groups present in the siloxane. The amino groups may be present in the siloxane as aminoethyl groups, aminopropyl groups, aminoisobutyl groups, aminoethylaminopropyl groups, or aminoethylaminoisobutyl groups. Reference may be had to recently issued U.S. Pat. No. 6,475,974 (Nov. 5, 2002), for details of these and similar siloxanes containing amino groups, which can be used herein.
Component (iii) used in the process is a surfactant, and this component may comprise a nonionic surfactant, a cationic surfactant, an anionic surfactant, or a mixture of such surfactants. Most preferred-however are nonionic surfactants.
Generally, the nonionic surfactant should be a non-silicon atom containing nonionic emulsifier. Most preferred are alcohol ethoxylates R4-(OCH2CH2)aOH, particularly fatty alcohol ethoxylates. Fatty alcohol ethoxylates typically contain the characteristic group xe2x80x94(OCH2CH2)aOH which is attached to fatty hydrocarbon residue R4 which contains about eight to about twenty carbon atoms, such as lauryl (C12), cetyl (C16) and stearyl (C18). While the value of xe2x80x9caxe2x80x9d may range from 1 to about 100, its value is typically in the range of about 12 to about 40.
Some examples of suitable nonionic surfactants are polyoxyethylene (4) lauryl ether, polyoxyethylene (5) lauryl ether, polyoxyethylene (23) lauryl ether, polyoxyethylene (2) cetyl ether, polyoxyethylene (10) cetyl ether, polyoxyethylene (20) cetyl ether, polyoxyethylene (2) stearyl ether, polyoxyethylene (10) stearyl ether, polyoxyethylene (20) stearyl ether, polyoxyethylene (21) stearyl ether, polyoxyethylene (100) stearyl ether, polyoxyethylene (2) oleyl ether, and polyoxyethylene (10) oleyl ether. These and other fatty alcohol ethoxylates are commercially available under trademarks and tradenames such as ALFONIC(copyright), BRIJ, GENAPOL(copyright), NEODOL(copyright), SURFONIC(copyright), TERGITOL(copyright), and TRYCOL. Ethoxylated alkylphenols can also be used, such as ethoxylated octylphenol, sold under the trademark TRITON(copyright).
Cationic surfactants useful in the invention include compounds containing quaternary ammonium hydrophilic moieties in the molecule which are positively charged, such as quaternary ammonium salts represented by Rxe2x80x2Rxe2x80x3Rxe2x80x2xe2x80x3Rxe2x80x3xe2x80x3N+Xxe2x88x92 where Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3, and Rxe2x80x3xe2x80x3 are alkyl groups containing 1-30 carbon atoms, or alkyl groups derived from tallow, coconut oil, or soy; and X is halogen, i.e., chlorine or bromine. Most preferred are dialkyldimethyl ammonium salts represented by Rxe2x80x2Rxe2x80x3N+(CH3)2Xxe2x88x92, where Rxe2x80x2 and Rxe2x80x3 are alkyl groups containing 12-30 carbon atoms, or alkyl groups derived from tallow, coconut oil, or soy; and X is halogen. Monoalkyltrimethyl ammonium salts can also be employed, and are represented by Rxe2x80x2N+(CH3)3Xxe2x88x92 where Rxe2x80x2 is an alkyl group containing 12-30 carbon atoms, or an alkyl group derived from tallow, coconut oil, or soy; and X is halogen.
Some representative quaternary ammonium salts are dodecyltrimethyl ammonium bromide (DTAB), didodecyldimethyl ammonium bromide, dihexadecyldimethyl ammonium chloride, dihexadecyldimethyl ammonium bromide, dioctadecyldimethyl ammonium chloride, dieicosyldimethyl ammonium chloride, didocosyldimethyl ammonium chloride, dicoconutdimethyl ammonium chloride, ditallowdimethyl ammonium chloride, and ditallowdimethyl ammonium bromide. These and other quaternary ammonium salts are commercially available under tradenames such as ADOGEN, ARQUAD, TOMAH, and VARIQUAT.
Among the various types of anionic surfactants which can be used are sulfonic acids and their salt derivatives; alkali metal sulfosuccinates; sulfonated glyceryl esters of fatty acids such as sulfonated monoglycerides of coconut oil acids; salts of sulfonated monovalent alcohol esters such as sodium oleyl isothionate; amides of amino sulfonic acids such as the sodium salt of oleyl methyl tauride; sulfonated products of fatty acid nitriles such as palmitonitrile sulfonate; sulfonated aromatic hydrocarbons such as sodium alpha-naphthalene monosulfonate; condensation products of naphthalene sulfonic acids with formaldehyde; sodium octahydro anthracene sulfonate; alkali metal alkyl sulfates such as sodium lauryl (dodecyl) sulfate (SDS); ether sulfates having alkyl groups of eight or more carbon atoms; and alkylaryl sulfonates having one or more alkyl groups of eight or more carbon atoms.
Some examples of commercial anionic surfactants useful in this invention include triethanolamine linear alkyl sulfonate sold under the tradename BIO-SOFT N-300 by the Stepan Company, Northfield, Ill.; sulfates sold under the tradename POLYSTEP by the Stepan Company; and sodium n-hexadecyl diphenyloxide disulfonate sold under the tradename DOWFAX8390 by The Dow Chemical Company, Midland, Mich.
Component (iv) used in the process is one of (1) an aqueous phase consisting of water, (2) an aqueous phase containing water and a low molecular weight polysiloxane, preferably a volatile low molecular weight polysiloxane, and (3) an aqueous phase containing water and a polar solvent.
Some examples of suitable low molecular weight polysiloxanes include (a) low molecular weight linear and cyclic volatile methyl siloxanes, (b) low molecular weight linear and cyclic volatile and non-volatile alkyl and aryl siloxanes, and (c) low molecular weight functional linear and cyclic siloxanes. Most preferred, however, are low molecular weight linear and cyclic volatile methyl siloxanes (VMS).
VMS compounds have a structure corresponding to the average unit formula (CH3)bSiO(4-b)/2 in which b has an average value of two to three. The compounds contain siloxane units joined by xe2x95x90Sixe2x80x94Oxe2x80x94Sixe2x95x90 bonds. Representative units are monofunctional xe2x80x9cMxe2x80x9d units (CH3)3SiO1/2 and difunctional xe2x80x9cDxe2x80x9d units (CH3)2SiO2/2.
The presence of trifunctional xe2x80x9cTxe2x80x9d units CH3SiO3/2 results in the formation of branched linear or cyclic volatile methyl siloxanes. The presence of tetrafunctional xe2x80x9cQxe2x80x9d units SiO4/2 results in the formation of branched linear or cyclic volatile methyl siloxanes.
Linear VMS have a structure corresponding generally to the formula (CH3)3SiO{(CH3)2SiO}cSi(CH3)3. The value of c is 0-5. Cyclic VMS have the formula {(CH3)2SiO}d. The value of d is 3-9. Preferably, these volatile methyl siloxane have a boiling point less than about 250xc2x0 C. and viscosity of about 0.65 to about 5.0 mm2/s.
Representative linear volatile methyl siloxanes are hexamethyldisiloxane (MM) with a boiling point of 100xc2x0 C., viscosity of 0.65 mm2/s, and formula Me3SiOSiMe3; octamethyltrisiloxane (MDM) with a boiling point of 152 xc2x0 C., viscosity of 1.04 mm2/s, and formula Me3SiOMe2SiOSiMe3; dccamethyltetrasiloxanc (MD2M) with a boiling point of 194xc2x0 C., viscosity of 1.53 mm2/s, and formula Me3SiO(Me2SiO)2SiMe3; dodecamethylpentasiloxane (MD3M) with a boiling point of 229xc2x0 C., viscosity of 2.06 mm2/s, and formula Me3SiO(Me2SiO)3SiMe3; tetradecamethylhexasiloxane (MD4M) with a boiling point of 245xc2x0 C., viscosity of 2.63 mm2/s, and formula Me3SiO(Me2SiO)4SiMe3; and hexadecarnethylheptasiloxane (MD5M) with a boiling point of 270xc2x0 C., viscosity of 3.24 mm2/s, and formula Me3SiO(Me2SiO)5SiMe3.
Representative cyclic volatile methyl siloxanes are hexamethylcyclotrisiloxane (D3) a solid with a boiling point of 134xc2x0 C. and formula {(Me2)SiO}3; octamethylcyclotetrasiloxane (D4) with a boiling point of 176xc2x0 C., viscosity of 2.3 mm2/s, and formula {(Me2)SiO}4; decarnethylcyclopentasiloxane (D5) with a boiling point of 210xc2x0 C., viscosity of 3.87 mm2/s, and formula {(Me2)SiO}5; and dodecarnethylcyclohexasiloxane (D6) with a boiling point of 245xc2x0 C., viscosity of 6.62 mm2/s, and formula {(Me2)SiO}6.
Representative branched volatile methyl siloxanes are heptamethyl-3-{(trimethylsilyl)oxy}trisiloxane (M3T) with a boiling point of 192xc2x0 C., viscosity of 1.57 mm2/s, and formula C10H30O3Si4; hexamethyl-3,3, bis {(trimethylsilyl)oxy} trisiloxane (M4Q) with a boiling point of 222xc2x0 C., viscosity of 2.86 mm2/s, and formula C12H36O4Si5; and pentamethyl {(trimethylsilyl)oxy} cyclotrisiloxane (MD3) with the formula C8H24O4Si4.
Component (iv) may also include low molecular weight linear and cyclic volatile and non-volatile alkyl and aryl siloxanes represented respectively by the formulas R3SiO(R2SiO)nSiR3 and (R2SiO)x. R can be alkyl groups with 2-20 carbon atoms or aryl groups such as phenyl. The value of n is 0-80, preferably 5-20. The value of x is 3-9, preferably 4-6. These polysiloxanes have a viscosity generally in the range of about 1-100 mm2/s.
Polysiloxanes can also be used where n has a value sufficient to provide siloxane polymers with a viscosity in the range of about 100-1,000 mm2/sec. Typically, n can be about 80-375. Illustrative of such polysiloxanes are polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polymethylphenylsiloxane, and polydiphenylsiloxane.
Low molecular weight polysiloxanes containg functional groups can also be employed, and can be represented by structures corresponding to the formula R3SiO(RQSiO)nSiR3 where Q is the functional group and n is generally the same as defined above. Examples of such functional polysiloxanes containing functional groups represented by Q are acrylamide functional siloxane fluids, acrylate functional siloxane fluids, amide functional siloxane fluids, amino functional siloxane fluids, carbinol functional siloxane fluids, carboxy functional siloxane fluids, chloroalkyl functional siloxane fluids, epoxy functional siloxane fluids, glycol functional siloxane fluids, ketal functional siloxane fluids, mercapto functional siloxane fluids, methyl ester functional siloxane fluids, perfluoro functional siloxane fluids, polyisobutylene (PIB) functional siloxane fluids, silanol functional siloxanes, and vinyl functional siloxane fluids.
The polar solvents especially preferred herein are those compounds determined to be cosmetically acceptable non-aqueous polar solvents, among which are monohydroxy alcohols such as ethyl alcohol and isopropyl alcohol; diols and triols such as propylene glycol, 1,2-hexanediol CH3(CH2)3CH(OH)CH2OH, 2-methyl-1,3-propane diol HOCH2CH(CH3)CH2OH, and glycerol; glycerol esters such as glyceryl triacetate (triacetin), glyceryl tripropionate (tripropionin), and glyceryl tributyrate (tributyrin); and polyglycols such as polyethylene glycols and polypropylene glycols among which are PPG-14 butyl ether C4H9[OCH(CH3)CH2]14OH. In applications other than personal care, these and other non-aqueous polar solvents can be employed.
The aqueous polar phase of the emulsion or microemulsion therefore, can consist of water, a mixture of water and a low molecular weight polysiloxane, or a mixture of water and a polar solvent which is preferably a polar organic compound. Generally, this component will be present in the composition in an amount to provide the balance of the composition to 100 percent, after taking in account the amounts of the other components used in formulating a suitable composition. Typically, however, this component will comprise 0.1-99.8 percent by weight based on the total weight of the O/W or W/O emulsion or microemulsion composition, preferably 1-80 percent by weight, and more preferably 3-10 percent by weight. While mixtures of liquids can be used to form this single phase component of the composition, liquids should be miscible and capable of forming an essentially homogeneous mixture.
Since emulsions and microemulsions are susceptible to microbiological contamination, a preservative may be required as an optional component of the composition, and some representative compounds which can be used include formaldehyde, salicylic acid, phenoxyethanol, DMDM hydantoin (1,3-dimethylol-5,5-dimethyl hydantoin), 5-bromo-5-nitro-1,3-dioxane, methyl paraben, propyl paraben, sorbic acid, imidazolidinyl urea sold under the name GERMALL(copyright) II by Sutton Laboratories, Chatham, N.J., sodium benzoate, 5-chloro-2-methyl-4-isothiazolin-3-one sold under the name KATHON CG by Rohm and Haas Company, Philadelphia, Penn., and iodopropynl butyl carbamate sold under the name GLYCACIL(copyright) L by Lonza Incorporated, Fair Lawn, N.J.
A freeze/thaw stabilizer can be included as another optional component of the composition including compounds such as ethylene glycol, propylene glycol, glycerol, trimethylene glycol, and polyoxyethylene ether alcohols such as RENEX 30 sold by ICI Surfactants, Wilmington, Del.
Another optional component of the composition which can be included is a corrosion inhibitor such as an alkanolamine, an inorganic phosphate such as zinc dithiophosphate, an inorganic phosphonate, an inorganic nitrite such as sodium nitrite, a silicate, a siliconate, an alkyl phosphate amine, a succinic anhyoride such as dodecenyl succinic anhydride, an amine succinate, or an alkaline earth sulfonate such as sodium sulfonate or calcium sulfonate.
When O/W or W/O emulsion or microemulsion compositions according to this invention are used in particular product(s) intended for the personal care market, the compositions may be formulated to include one or more alternate components, for example:
(A) conditioning agents such as cationic polymers, proteins, natural oils, polysiloxanes other than quaternary ammonium functional polysiloxanes, hydrocarbon other than waxes, and mixtures thereof;
(B) cosurfactants such as betaines, monoalkylalkanolanides, dialkylalkanolamides, amine oxides, amine glycinates, amine propionates, amine sultaines, and mixtures thereof;
(C) polyhydric alcohols such as glycerin and sorbitol.
Products containing alternate components (A) are especially useful as conditioners, products containing (A) and (B) are especially useful as shampoos, and products containing (C) are especially useful as moisturizers.
The amount of each of the various components used in preparing emulsions and microemulsions according to the invention, based on the total weight of the composition, is:
(i) 0.01-90 percent by weight of the organic quaternary ammonium compound having epoxide groups or halohydrin groups in its molecule;
(ii) 0.01-90 percent by weight of the silane or the siloxane having amino groups in its molecule;
(iii) 0.01-90 percent by weight of the surfactant, preferably 2-40 percent by weight, more preferably 5-20 percent by weight; and
(iv) the balance to 100 percent by weight being the aqueous polar phase.
If an optional component is included, it is generally present in an amount of 0.01-0.1 percent by weight of each optional component, i.e., preservative, freeze/thaw stabilizer, or corrosion inhibitor.
The reaction can be made to take place by simply mixing all of the components together, and this is the minimum requirement to obtain reaction, i.e., to perform the xe2x80x9creactingxe2x80x9d step under the circumstances. However, it is generally preferred to mix all of the reactants together and to heat them. A catalyst is typically not necessary but under some circumstance, an appropriate catalyst may be employed. In this regard, it has been found that in general, tertiary amines do not add readily to epoxides. This can be improved if the reaction mixture is acidified, especially in stoichiometric proportions, or the tertiary amine is pretreated with an acid in order to convert it to its acid salt.
The emulsions and microemulsions can be prepared using simple propeller mixers, turbine-type mixers, Brookfield counter-rotating mixers, or homogenizing mixers. No special equipment or processing conditions are generally required.